Elements | EvaEsi Dev

Overview

Elements is the coding model and the explicit entry point for Studio work. Route through Elements directly when you want code, structured edits, or deterministic file-shaped output without the evidence-gather pass that Reasoning runs.

Endpoint

POST https://evaesi.dev/api/v1/responses

Pass "model": "elements" to route here. Older callers can use "code", "coding", "element", "esielement", or "esielement-1": the gateway normalises them all to elements.

Use Cases

Writing new code from a natural-language description
Refactors, renames, and structured edits across a file or snippet
Code review, explanation, and translation between languages
Studio-grade output (test scaffolds, config blocks, schemas) where shape matters

Limits

Field	Value
Max input rungs	`100,000`
Max output rungs	`64,000`
Context window	`4,096` model bytes (billing rungs are a separate unit)
Streaming	Yes
Batch	No. The route is mounted but returns `503 EVA_UNAVAILABLE`
Tools	No

Billing

Elements is billed at the base rate, 1.0×. Input and output rungs are metered separately and reported on usage plus the x-evaesi-*-rungs headers.

The request

Field	Type	Required	Description
`prompt`	string	Yes	Prompt text. Max 100,000 bytes.
`model`	string	Yes	Pass `"elements"` to route here.
`max_output_rungs`	u64?	No	Output cap, validated against the model's 64,000 limit (`400 INVALID_REQUEST` above it). Falls back to 64,000.
`code_mode`	bool	No	Hint the dispatcher this is code work.
`stream`	bool?	No	Server-sent event streaming.

Response

{
  "request_id": "req_a112...",
  "content": "fn parse(input: &str) -> Result<Doc, ParseError> {\n    ...\n}",
  "sources": [],
  "sources_url": "/api/v1/sources/req_a112...",
  "usage": {
    "input_rungs": 412,
    "output_rungs": 1180,
    "total_rungs": 1592
  },
  "model": "elements"
}

Examples

cURL

curl -X POST https://evaesi.dev/api/v1/responses \
    -H "Authorization: Bearer esi_dev_YOUR_KEY" \
    -H "Content-Type: application/json" \
  -d '{
    "prompt": "Write a Rust function that parses RFC3339 dates without external crates.",
    "model": "elements",
    "code_mode": true,
    "max_output_rungs": 4096
  }'

Python

import requests

response = requests.post(
    "https://evaesi.dev/api/v1/responses",
    headers={"Authorization": "Bearer esi_dev_YOUR_KEY"},
    json={
        "prompt": "Write a Rust function that parses RFC3339 dates without external crates.",
        "model": "elements",
        "code_mode": True,
        "max_output_rungs": 4096,
    },
)

data = response.json()
print(data["content"])

JavaScript

const response = await fetch("https://evaesi.dev/api/v1/responses", {
  method: "POST",
  headers: {
    "Authorization": "Bearer esi_dev_YOUR_KEY",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    prompt: "Write a Rust function that parses RFC3339 dates without external crates.",
    model: "elements",
    code_mode: true,
    max_output_rungs: 4096,
  }),
});

const data = await response.json();
console.log(data.content);

Start from a live reference page.